Genetics 07: Man or Woman

Babies start developing gender in the early stage of the conception, the sex cells would suppress the opposite gender of the embryo based on the genes. Women have a pair of X chromosomes, and men have a X chromosome and a Y chromosome. The SRY genes in Y chromosomes is responsible for making the baby a boy, but there is a complex interaction going on behind this gene and it is not the only factor that decides the gender of a baby. A gene called DMRT1 keeps the stability of gender developments. If this gene is missing, the sex cells will start behaving in both gender and cause potential problem for the baby.

The Y chromosome was originally thought to only have the function of determine the maleness of an individual, but there is actually more than that. The X and Y chromosomes originated from the same chromosome, but the Y chromosome shrunk and it now contains around 20 times less genes than the X chromosomes. Scientists compared the Y chromosomes of various mammals and found out that they share similarities and have genes that could affect other parts of the genome. We figured out that the reason why our Y chromosome didn't shrink away completely is because they hold these dosage-dependent genes that are vital to our survival.